Duplex switch for telephones



No. 623,352. 7 Patehted Apr. I8, I899. a. c. BUELL.

DUPLEX SWITCH FOB TELEPHONES.

(Application filed Aug 15, 1898.)

(No Model.)

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UNITED STATES PATENT OFFICE.

GEORGE G. BUELL, OF BOSTON, MASSACHUSETTS.

DUPLEX SWITCH FO R TELEPHONES.

SPECIFICATION forming part of Letters Patent No. 623,3 52, dated April18, 1899. v Application filed August 15, 1898. Serial No. 688,600. (Nomodel.)

' To all whom it may concern:

Be it known that I, GEORGE O. BUELL, 0 Boston, county of Suffolk, Stateof Massachusetts, have invented an Improvement in Duplex Switches forTelephones, of which the following description, in connection with theaccompanying drawings, is a specification, like letters on the drawingsrepresenting like parts. 7

My invention is a duplex switch for telephones,'being particularlyintended for use Where an auxiliary instrument is found desirable on asubscribers premises, said switch being capable of automaticallycutting. said auxiliary telephone in and out of the main line, asdesired.

My invention will be more definitely described hereinafter in connectionwith the accompanying drawings, illustrative of a preferred embodimentthereof, and the invention will be more particularly defined in theappended claims.

In the drawings, Figure 1 shows in side elevation a simple embodiment ofmy invention, the circuit connections therefor being indicateddiagrammatically. Figs. 2 and 3 are similar views illustrating thepositions the parts assume in use.

Inasmuch as the telephone itself and the wiring and variousappurtenances thereof form no essential feature of my invention and maybe of any usual or preferred kind, I have not deemed it necessary toindicate herein more than is sufficient merely to make myinventionunderstood.

1n the drawings, a indicates an automatic switch pivoted at-a' andhaving a bifurcated hook-like end a to receive a receiver R in usualmanner, this lever being herein shown as actuated byaspring 8 againstthe gravity of the receiver R.

Forming a practical continuation of the lethe path of a shoulder of onthe member a, so

that the member a may move down independently of the member a; but ifthe receiver is removed from its hook the entire switch will necessarilybe moved, as indicated in Fig. 3.

The member a of the switch is normally sustained by any suitable means,a spring 8' being herein shown for the purpose, and said member a isinsulated by any convenient means from the forward part of thelever,'being herein shown as itself formed of ebonite or indurated fiberand provided with brasses or other contact-blocks a a to contact withthe required'springs orcontacts of the circuits.

I have herein indicated a common arrangement of the various contacts,and inasmuch as this will be readily understood without er;-

planation I will simply mention that the contacts b b are to the mainline b b are to the primary instrument thereof, such as is usu- I allyin charge of a telephone attendant or normally left for the routinebusiness of the establishment, it being supposed thatthe instrumentherein shown is the one, for example, in the presidents office, andwires 19 and call, this operation, however, not disturbing the member aof the switch, the only effect so far having been to transfer the twomainline connections from the primary instrument to the secondaryone.When, however, the operator removes his finger from the member a thespring 8" thereof immediately breaks the auxiliary circuit and restoresthe primary telephone to the main line, as before. When the operatorremoves the receiver, the parts assume the position shown in Fig. 3, itbeing understood that the spring 8 or other automatic actuator thereofis stronger than the corresponding part 8, and therefore compels the twoparts of the switch-lever to move together in interlocked relation.

By my invention it isimpossible for the operator to leave the apparatusout of its normal position, for the reason that the moment the finger isremoved from the lever a its spring restores it to the position in Fig.1, and similarly it is restored whenever the receiver is hung on itshook after use, thereby automatically putting the primary instrument incircuit again for its ordinary use,which has been temporarily suspendedduring the use of the line-Wires by the auxiliary.

No provision is here made for signaling from the primary to theauxiliary telephones, which may be done independently; but this featureis not material to the invention. More than one of these auxiliaryinstruments may be employed, connected in series, each when in usecutting out all beyond it on the line.

When the receiver R of the auxiliary instrument is hung on the leveraandthe member a thereof is in the position indicated in Fig. 1, then thecircuit is as follows: from the central station to contact I), thencethrough block a to contact 12 and to the primary instrument and back tocontact b to block a contact I), and thence back to the central station,and when the member a is depressed, as in Fig. 2, the circuit is fromthe central station to I), through a to b to I), through arm a andspring 8 tob a to b, and thence again to central, and when the parts arein the positions shown in Fig. 3 the line or secondary circuit is fromthe central station to contact I), block a to contact b to I), througharm or lever a to spring 8 to contact 11 block 0. to b, and thence tothe central station, and the local circuit is from battery on thepremises through wire 1), arm a, spring 3, transmitter 19 and back tobattery.

My invent-ion relates, as before explained, to a provision whereby aninstrument termed herein for convenience an auxiliary instrument andanother instrument termed herein for convenience the primary instrument,which may be in the same office or building and are on the same mainline, the primary instrument being normally connected into the main lineand the auxiliary instrument cut out from the main line, so that, forexample, when central calls the oiiice the call will go to the primaryinstrument and will there be attended to and will not reach theauxiliary instrument in any manner; but if a person wishes to use theauxiliary instrument my invention enables said person automatically tocut out the primary instrument there at the office and out in theauxiliary instrument, and also enables said person (by depressing thelever a as shown in Fig. 2) to call up central independentlyof theprimaryinstrument,and with the certainty that upon raising the fingerthe auxiliary apparatus will automatically restore the parts to theirnormal position, placing the primary instrument in the line and entirelycutting out the auxiliary instrument therefrom.

Having described my invention, what I claim as new, and desire to secureby Letters Patent, is-

1. In a telephone apparatus where two or more instruments are used atone .end of a main line, a switch, including a member for supporting thereceiver and performing the usual operations of an automatic switch, incombination with switching mechanism for transferring the main-lineconnections from one instrument to another, operated by said supportingmember, but capable, when desired, of being operated independently ofsaid supporting member, substantially as described.

2. In a telephone apparatus, a switch includin g areceiver-hook,performing the usual operations of an automatic switch, together withswitching mechanism for transferring the line connection from oneinstrument to another, said receiver-hook and said switching mechanismbeing operable dependently or independently, at will, substantially asdescribed.

3. In a telephone apparatus, a switch including a member for supportingthe receiver, and performing the usual operationsof an automatic switch,in combination with switching mechanism capable of operatingindependently of said supporting member, for transferring the lineconnection from the primary instrument to an auxiliary instrument, saidswitching mechanism having means independent of said supporting memberfor antomatically restoring it to its normal position, substantially asdescribed.

. 4. The herein-described duplex switch for telephones, comprising alever made in two parts, one part being adapted to support the receiverand perform the usual operations of an automatic switch, and the otherpart being providedwith means automaticallymaintainingit in a givenposition, said two parts being connected to move together on the removalof the receiver, but the other end of the lever being capable ofindependent operative movement when the receiver end of the lever isdown, substantially as described.

5. A two-part switch-lever for telephone apparatus, one part of which ismovable independently of the other in one position of the latter, andmoved and controlled by the movement of the said latter, and means assprings normally tending to move said two partsin opposition to eachother, substantially as-described.

6. The herein-described duplex switch for telephones, comprising a levermade in two parts, one part being adapted to support the receiver andact as an automatic switch, and the other part being provided with meansnormally maintaining it in a given position, said part being manuallymovable independently of the said supporting part, said two parts beingconnected to move together on the removal of the receiver, substantiallyas described.

7. A two-part switch-lever for telephone apparatus, said two parts beinginterlocked to move in unison by the movement of one part, the otherpart being manually movable in one direction independently of the last-mentioned part, and means normally holding said two levers in a givenrelation, with said manuallymovable part out of its said mannally movedposition relatively to the other part, substantially as described.

8. A two-part switch-lever for telephone apparatus", said two partsbeing pivoted together and projecting in opposite directions, one

part being movable on its pivot independently of the other part when thelatter is in one position, means normally holding said two parts in agiven relative position, said independently-movable part beingautomatically moved by the movement of said other part and Withoutchanging the normal relative position of the said two parts,substantially as de-

